It has long been known to react substrates having active hydrogen atoms with alkylene oxides to give products useful in specialty plastics and as surfactants. For instance, bisphenol A (4,4′-isopropylidenediphenol or 2,2-bis(4-hydroxyphenol)propane), is known as an intermediate for epoxy resins and poly-carbonate resins. The reaction of bisphenol A with ethylene oxide (EO) may be typically done without a solvent in a molten state at temperatures in the range of about 160 to about 170° C. However, it is well recognized that ethylene oxide is very volatile, and at these temperatures there are safety concerns. Disadvantages of producing EO adducts of bisphenol A at these temperatures include the requirement of using a special, oil-heated reactor system that is more costly as compared with a more commonly used steam-heated reactor system that most operators prefer. Conventionally, alkoxylating high melting point substrates, such as bisphenol A, requires special insulation of and heat-tracing of the pipes, valves and other equipment. Also, the substrates can readily solidify during the taking of samples for analysis, which solidification causes plugging of valves and lines and which, in turn, creates costly down-time and shut-time of the reactor and/or manufacturing process. Further, heating such substrates to their melting points for alkoxylation increases the tendency of the formation of more undesirable degradation products, by-products and color, possibly due to the effects of heating the product. There has been considerable effort over at least the last ten years by many companies to alkoxylate high melting point substrates but avoiding a discolored product, without success.
It would thus be desirable to provide a method for alkoxylating substrates with active hydrogens that could be conducted at relatively lower temperatures to reduce safety concerns, to allow the use of more commonly available and less costly steam-heated reactor systems, and also to possibly reduce the color of and the amount of undesirable degradation by-products in the alkoxylated product.